Car-spring



' (No Model.)

T. J. MAYALL.

GAR SPRING.

and into which air will be drawn when the load I chamber within the spring.

thefolowing is a specification.

THOMAS J. MAYALL, or READING, ASSIGNOR 'ro PATENT FFICEQ.

THE BRUNSW'IUK ANTI- MONY COMPANY, OF BOSTON, MASSACHUSETTS.

CAR-SPRING.

SPECIFICATION forming part of Letters Patent No. 286,042, dated October 2, 138?. Application filed March 19, 18593. (No model.)

To all whom; it may concern.-

Be it known that I, TiroivrAsJ. MAYALL, of Reading, in the'eounty of Middlesex and Oom- I monwealth of Massachusetts, have invented an Improved Spring for Railroad-Cars, of which My invention relates to that class of carsprings which are made of rubber in the form of a cylinder, the object of it being to make a spring which will cost considerably less than the rubber springs heretofore made, and which will have greater elasticity and durability; and it consists in so making the cylindrical rubber spring that it will have one or more air-chambers within it, in which the air will be compressed by the pressure of theload,

is raised by the motion of the car.

I11 the drawings annexed, Figure 1. shows a side and bottom perspective of my improved carspring, with the central hole and air-passage from it, and also the air-opening to the Fig. 2 shows a longitudinal sectional view th rough the center of the spring, and the air-chamber within it, and the iron caps on both ends of it. Fig. 3 shows a cross-sectioual view of the spring at near the bottom of it. Fig. 4c shows a spring broken transversely near the middle.

, lhe letters used indicate the same partsin all the figures.

A indicates the outer wall of the spring.

A indicates the end walls of the spring.

A indicates the central. .hole through the spring, which, being closed at both ends by the metallic caps 011 both ends of the spring, is made an air-chamber.

A. indicates the air-passage from the central hole through the spring, which forms the central air-chamber to the outercircumference of the spring. It is a shallow groove in the rubber, which will be closed as the load presses on the spring, and will open when the load rises. y

A" indicates an opening from the annular air-chamber in the body of the springto the air-passage A, by which air may enter into or pass from the annular chamber in the spring. A 111 dicates an annular chamber in the body than has heretofore been used for of the spring,which is closed by the side and end walls of the spring at all points except the passage A and A".

A" indicates metallic caps one on each end of the springwhich inclose and support the cornersof the spring.

A indicates an annular wall of rubber between the central hole through the spring and the annular air-chamber A, which is jointed to the endwalls of the spring A.

A indicatesa metallic pin or bolt extending through both the metallic caps A"',with a head on one end and a nut on the other,with a packing-washer under both heads and nuts, the spindles of the bolt extending through the central hole in'the spring, though filling only a part of the space, being of about half the diameter of the central hole.

This spring is made wholly of rubber, vulcanized or cured in the usual manner of curing rubber for car-s n'ings.

A better article of "rubber for ear-springs that pnrpose ismade by compounding with. pure rubher about an equal quantity, by weight, of penta-sulphide or golden sulphuret of ant1- mony, the rubber so compounded having much greater strength, elasticity, and durability; but as I have made this the subject 01' another application for a patent, I will not describe it further here.

I make this spring by sheet-rubber prepared for val canizin g, as wide as the length of the spring, on a mandrel of the diameter required for the central hole, as thick as the annulaizwall A is to be. A metallic former or mold of the dimensions required for annular chamber A is then placed around the rubber for the wallv A and sheet plastic rubber prepared for vulcanizing is Wound around the mold suiiicient to make the annular outside wall, A. A mold is prepared the inside dimensions and form of which are exactly what the outside dimensions and forni of the finished spring are to be. Disks of plastic sheet-rubber prepared for vulcanizing are cut out sufficient to make the end walls of the spring, and. enough for one end wall of the spring is placed in one end of the mold. The

winding up plastic rubber to form the annular outer walls of the springs is then placed in the mold in contact with the disks for this end wall, and the rubchamber in the spring, and the central mandrel, having been removed, the plastic rubber disks to form the outer end wall of the spring are placed in the mold, a hole having been punched in the rubber for the air-opening A. There will be projections on the inside of the mold to form the air-openings A and A. The mold being tightly closed and placed in the curing or vulcanizing oven, the air in the chambers of the spring, being confined so that it cannot escape, will be so expanded by the heat'of the oven, which will be from 250 to 275 Fahrenheit, that the outer annular walls of the spring will be forced against the inside of the mold with considerable force, so that when the spring is cured it will closely fit the mold, and the inner annular wall between the annular chamber and the central hole in the spring will, in consequence of having had an equal pressure of the heated and expanded air on both sides of it, remain in the position in which it was placed in the mold, and the outer annular wall and the inner annular wall, and both end walls of the spring,will be by the heat of the oven and the pressure of the heated air in the chamber and central hole firmly welded together in one homogeneous whole, and capable of withstanding the pressure of the load on the spring, and the air-pressure in the annular chamber and central hole, which the load 011 the spring may produce.

I claim as new and of my invention 1. A rubber ear-spring of cylindrical shape, comprising a central longitudinal air-chamber and a second surrounding air-chamber, the end wall of the spring having a groove which communicates by small openings with said airchambers, substantially as described.

2. The combination of the rubber spring having air-chambers, as explai ed, and the metal caps, the face of the rubber spring being provided between it and the adjacent cap with ashallow groove communicating with said airchambers, substantially as described.

THOS. .T. MAYALL.

Witnesses:

OHs. HoUGH'roN, J. E'PIcKnRINc. 

